Syntax highlighting for closure.requires(args) and closure.ensures(args)

[y1ca1]

Currently, verus-analyzer reserves the keyword requires and ensures so the special syntax for closure pre/post-condition on args is not well recognized:

It would be nice if this kind of valid Verus syntax can be recognized.

I guess the parser would need to introduce some more context-sensitivity/hack to get the correct syntax highlighting for these clauses.